(1) Field of the Invention
The invention relates to a document moving transmission system for an optical scanner, and more particularly to an optical scanner with mechanism for original document moving and capable of maintaining and adjusting surface flatness of the window assembly over the light transmitting slot of the optical scanner.
(2) Description of the Prior Art
Generally, for an optical scanner to have a satisfied resolution, it is quite important to reduce overall tolerance accumulated during manufacturing and assembling. In the case of an optical scanner with a document moving mechanism, the overall tolerance is not only essential, but the flatness of the window assembly over the light transmitting slot is also crucial. It is easy to understand that the movement of the window assembly over the optical scanner forms a dynamic system on top of the optical scanner. It is then inevitable that, after years usage, the fitting between components will become loosen more or less. Thus, on the sad side, the flatness of the window assembly over the light transmitting slot will lose as well; which will critically affect the resolution and quality of the imaging.
Moreover, no convenient way for flatness re-adjusting at field is available so far to meet necessary in-site maintenance. As long as the optical scanner leaves the assembly line, it is quite difficult to have the flatness of the window assembly calibrated. As a matter of fact, the looseness between components will prevail to a negative side, and make the maintaining of flatness over the window assembly unfeasible. Consequently, the deteriorating of imaging quality can be expected.
To overcome the possible misalignment issue, it is usually devoted to the manufacture process; such as increasing the machining accuracy and reducing the fitting tolerance. However, resort in these folds just implies a trade-off in cost-increasing, which might harm the sales. Therefore, a preferable way shall be determined to resolve the dilemma between the imaging accuracy and the competitiveness.